A number of patents and patent application publications disclose structure and technology related to warning devices and systems that can be employed in a mobile environment. Each or the patents and publications referenced herein is hereby incorporated by reference in its entirety. U.S. Pat. No. 7,523,000, dated Apr. 21, 2009, describes a system of communication among cars, stationary towers, and satellites. When a rear-end collision is predicted, the system accelerates the vehicle in front to avoid the collision.
U.S. Patent Application Publication US 2008/0055068 A1, dated Mar. 6, 2008, describes broadcasting warning messages among mobile nodes at optimal power levels to avoid network overload. A communication device senses a danger and triggers a warning message to be forwarded to neighboring vehicles. Received messages may be retransmitted to other vehicles. U.S. Patent Application Publication US 2010/0134271 A1, dated Jun. 3, 2010, describes a visual warning system from one car to another. A driver who sees a hazard can press a button. An indicator will then illuminate; other drivers who see the indicator will then know of the hazard, and can plan accordingly. The warning may also be transmitted wirelessly; drivers who have similarly equipped cars may receive an in-car warning even when they cannot see the other car's indicator.
U.S. Patent Application Publication US 2010/0114467 A1, dated May 6, 2010, describes a vehicle with sensors to determine when nearby vehicles have crashed, by determining that their speeds have fallen outside of normal ranges. This information may then be transmitted to other vehicles by vehicle-to-vehicle communications or by flashing lights. U.S. Patent Application Publication US 2010/0114418 A1, dated May 6, 2010, describes a vehicle with sensors to determine when nearby vehicles have crashed, by determining their movement outside of normal traffic lanes. This information may then be transmitted to other vehicles by vehicle-to-vehicle communications or by flashing lights.
U.S. Patent Application Publication US 2010/0020169 A1, dated Jan. 28, 2010, describes a system that communicates with other vehicles. When a collision is predicted based on speed data from other vehicles, the system directs the driver where to go (e.g., change lanes) to avoid collision. U.S. Patent Application Publication US 2007/0063824 A1, dated Mar. 22, 2007, describes a system that can receive data from road construction transmitters, emergency vehicle transmitters, or other vehicles concerning road hazards. The system can also repeat signals to other vehicles. U.S. Patent Application Publication US 2008/0275618 A1, dated Nov. 6, 2008, describes an alert system to warn drivers when vehicles ahead are moving more slowly than normal. The vehicles transmit their speed data to each other, and large speed discrepancies generate warnings to drivers. Other conditions may also be transmitted, such as hazard signal state (on or off) or trunk or door position (open or closed).
EP 1 149 371 B1, published Oct. 31, 2001, describes a system of changing speed limits and speed bump size remotely and reporting collision information to first responders, traffic enforcement, etc. Communication is from a fixed point on or near a road to police, then to specific mobile officials as necessary.
International Publication WO 2009/140514 A2, dated Nov. 19, 2009, describes a fleet of vehicles communicating with one another. Follower vehicles operate autonomously based on data from the leader vehicle. International Publication WO 2010/055509 A1, dated May 20, 2010, describes a vehicle subsystem that collects information about the state of the vehicle. Information is communicated with a remote central server, which also transmits hazard information back to the vehicle and to other vehicles.
A number of articles and publications also describe relevant structure and technology. The article titled “A Shake May Prevent a Crash,” Science Now, news.sciencemag.org/sciencenow/2009/05/26-02.html, May 26, 2009, describes using radar or lasers to detect impending collisions, then warning drivers via tactile warnings. The article titled “Car tech: Building the zero-fatality car,” Computerworld, worldwideweb.computerworld.com/s/article/print/9179697/Car_tech—Building_the_zero_fatality_car, Aug. 5, 2010, describes sending out a “safety state—for example, the car's speed, the level of brake pressure the driver has applied and steering—to every other car in the vicinity.” Similarly, the article “Crash Warning for Connected Cars?,” ICT Results, worldwideweb.ec.europa.eu/information_society/activities/policy_link/documents/ict_results_factsheets/reposit.pdf, describes connected cars sharing their position, speed, and trajectory. A car receiving such data can then calculate the vehicles' relative positions to predict collisions. The publication “Features that prevent crashes,” NZ Transport Agency, 210.48.109.8/vehicle/choosing/features-prevent.html, Dec. 1, 2009, describes collision warning and avoidance systems that depend on a supporting network within the road system.